Yarn tensioning means for knitting machines



March 22, 1966 F. P. TRUMPIO 2,929,233

YARN TENSIONING MEANS FOR KNITTING MACHINES Filed April 29, 1955 2Sheets-Sheet 1 INVENTOR.

Ennis B Trum m'o "dz/a4;

A TTORNE Y.

March 22, W60 F. P. TRUMPIO 2,2,23

YARN TENSIONING MEANS FOR KNITTING MACHINES Filed April 29, 1955 2Sheets-Sheet 2 l LE1 E F .L|E.

. 60 60 'y; if- 2 IN V EN TOR.

Frank I? ffium m'o A TTORNE Y.

YARN TENSIONING MEANS FOR KNITTING MACHINES Application April 29, 1955,Serial No. 04,714

1 Claim. or. 66-86) This invention relates to warp knitting machinessuch as tricot machines, and more particularly to means in such machinesto take up the yarns and maintain a constant and uniform tension in theyarns during knitting of the same into fabric.

In textile fabricating machines such as tricot knitting machines and thelike, a plurality of sheet of yarns are withdrawn from supply beams andare fed or directed along a predetermined path to the needles orfabricating means where they are formed into fabric. Between the supplybeams and the needles the yarns pass over guiding and tensioning meanswhich continuously acts to take up and maintain the yarns underpredetermined tension as the needles are operated to knit the yarn intoloops. In a usual form, the tensioning means includes a rod extendingalong the full length of the working portion of the machine, the rodbeing carried on the ends of levers which are supported for oscillatingmovement on a shaft fixed in the framework of the machine. The movementsof the levers are controlled by springs or the like which act onportions of the levers at the other side of the supporting shaft toresiliently maintain the rod in engagement with the yarns and permit thelevers and rod to oscillate to follow the fluctuating demands for theyarns. With this construction the pressure exerted by the yarn and thesprings on the levers at opposite sides of the supporting shaftincreases the friction in the lever bearings on the supporting shaftwhich together with the weight mass of the levers and guide rod preventsthe sensitive oscillating movements of the parts necessary to maintainthe yarns under a uniform tension. This is particularly so in ma chinesoperating at high speeds, and results in the uneven feeding of the yarnsand the formation of fabric of inferior quality.

In other known forms of tensioning means, the rods are mounted on thinflexible sheet metal plates or other resiliently controlled means fixedon a supporting shaft adjustably mounted in the machine frame. In thesedevices the shaft is adjustable to vary the initial tension applied tothe yarns but there is no way to adjust the resilient means atindividual points along the rod to correct variations of tension withthe result that an uneven tension is applied to the yarns by differentparts of the guide rods.

It is accordingly an object of the invention to provide means in a warpknitting machine for uniformly applying tension on the yarns which meansis more economical to manufacture than known types and which willovercome the above mentioned and other difficulties.

Another object of the invention is to provide means for tensioning aplurality of yarns, particularly for use in tricot knitting machines,which means is carried on spaced members which are controlled byresilient means having individual adjustment to permit exertion ofuniform tension on all of the yarns.

A further object of the invention is to provide a guide rod fortensioning a plurality of yarns which guide rod is carried on spacedmembers which are pivoted about bearing surfaces having only pointcontact to thereby eliminate 2,929,233 Patented ar. 22, 1960 or reduceto a minimum friction between the bearing suurfaces. I

With these and other objects in view which will become apparent from thefollowing detailed description of the illustrative embodiment of theinvention shown in the illustrative embodiment of the invention shown inthe accompanying drawings, the invention resides in the novel elements,features of construction and cooperation of parts, as-hereinafter moreparticularly pointed out in the claim.

In the drawings:

Figure 1 is a cross-sectional view taken transversely through a portionof a tricot knitting machine showing the knitting mechanism and yarntensioning mechanism according to the invention, dot-and-dash distancebreaks being shown to indicate omission of intervening mechanism;

Fig. 2 is a plan view on an enlarged scale of the yarn tensioningmechanism as seen from the left of Fig. 1 and in the direction of thearrow A, certain parts of Fig. 1 being omitted;

Fig. 3 is an elevational view of the mechanism within the arrows 33 ofFig. 2, and shown on an enlarged scale relative to Fig. 2;

Fig. 4 is a cross-sectional view taken along the line 4-4 of Fig. 3;

Fig. 5 is a view partially in plan and partially in cross section takensubstantially on the line 5-5 of Fig. 3;

Fig. 6 is a cross-sectional view taken along the line 66 of Fig. 4; and

Fig. 7 is a cross-sectional view taken substantially along.

. for closing the beards of the needles and front and rear around theneedles by the yarn guides 15, into loops of p the fabric. The yarns 16,for the front and rear groups of yarn guides follow separate upper andlower paths, respectively, and are withdrawn from supply beams portionsof which are diagrammatically shown at 13 and 14, respectively. Theyarns 16 in the lower path pass beneath a rod or shaft 17 which issupported in spaced bearing brackets 20, partially shown in Figs. 1 and2, carried on a portion 21 of the framework of the machine. From the rod17 the yarns 16 pass through a comb device 22, carried in the brackets20, which acts to separate the individual yarns, and from the combdevice around a guide rod 24 to the rear group of yarn guides 15. Theyarns 16 in the upper path pass beneath a shaft 18 also supported in thebearing brackets 24 through a comb device 23 and over a guide rod 25 tothe front group of yarn guides 15.

During the knitting operation of the, machine the yarn guides 15 aremoved through the needles 10 from their position shown in Fig. 1, thenshifted transversely of the needle row and then back to the position ofFig. 1 to lap or loop the yarns around the needles and the needles aresimultaneously moved to catch yarns beneath thebeards and to form andknit the yarns into loops of the-fabric. This movement of the guidemembers 15 results in a variation in the demand for the yarns therebytending to cause a periodic increase and decrease in the tension in theyarns between the guide members and the guide rods 24 and 25. In orderto maintain a constant tension in the yarns at this time, the guide rods24 and 25 must be mounted to follow the rapidly varying demands for theyarns. For this purpose, the guide rod 24 for the yarns 16 in the lowerpath is carried in apertures in side walls 26 of each of a series enemas3 of spaced channel-shaped members or arms 27, the side walls beingconnected by an upper wall 30 (Figs. 3 and 4). A block member 31 issecured to the underside of the upper wall 30 intermediate the ends ofeach arm 27 by" screws 32. Each block member 31 is provided withal-shaped notch 34 for the reception of a knife-edge 35 forming the apexof a V-shaped portion 36 of a block 37, the knife edge and notch forminga pivot point about which thearms and guide rod 24 rocks duringvariations in the tension in the yarns. The block 37 is secured byscrews 40 to the free end of a support member or bracket 4d having itsother end 42 fixed on a rod 43 secured in the bearing brackets 29. Asshown in Fig. 2, the end 42 of the bracket 41 is forked to straddle thebearing bracket 20 and thereby maintain the support bracket in fixedposition axially of the rod 43. As shown in Fig. 6 the side walls 26 ofthe arm 27 engages the sides of the block 37 to hold the arm againstlateral shifting movement rela tive to the block. 6

Tension is applied to each arm 27 by a tension device 45 including acoil spring 48 which is adapted to be" pressed against the upper surfaceof the arm on the oppo'si te side of the pivot point from the rod 24.The block 31 has a portion 50 extending through a slot 51 in the arm 27and into the end of the spring 43 (Figs. and 6). A red 52 threadablycarried in the block 37 extends through the slot 51 and a correpsondingslot in the block 31 and through 'thespring 48. The spring 48 ispositioned on the rod 52 between the arms 27 and a shoulder portion 56formed internally of one end of a sleeve 57 mounted for sliding movementon therod S2. The other end of the rod 52 threadably carries lock or jamnuts 60 by means of which the sleeve 57 is adjusted axially of the rod52 to vary the pressure of the spring 48 on the arm 27 and thereby varythe tension applied by the guide rod 24 to the yarns. t

The guide rod 25 for the yarns 16 in the upper path .is mounted andtensioned by means which is identical in structure to the arms 27 andtension device 45 and acforked to straddle the bearing bracket 20 tomaintain the support bracket in fixed spaced relation on the rod 63" inwhich it clears the tension device 45 on the support bracket 41 (Fig.7).

From the foregoing it will be apparent that a light weight eflicienttenisoningdevice is provided by the instant invention attaining theaforesaid objects. Engagement ofthe knife-edge 35 in the notch 34provides a sub- In a warp knitting machine having means for supplyingaplurality of yarns and means for forming said yarns into a knittedfabric, the improvement comprising means for guiding and for applyingtension to said yarns between said supply means and said forming meansincluding a support member, a channel-shaped arm having side walls and awall joining said side walls, said side walls engaging opposite sidefaces of said support member, a guide rod for said yarns, apertures insaid side walls at one end of said arm for receiving said guide rod,spring means carried on said support member, said spring means actingonthe other end of said arm, and means for mounting said arrii on saidsupport member for pivotal movement including' a member escilred to saidjoining wall intermediate'said side walls of said arm and having anotch, and a V-sliaped projection on said support member intermediatesaid guide rod and said spring means for engagement in said notch.

Rear-amides Cited in the tire of this patent UNITED STATES PATENTS Browneta1. Sept. 15, 1953

